检索结果-南通市图书馆

Microstructural evolution and energetic characteristics of TiZrHfTa_(0.7)W_(0.3)high-entropy alloy under high strain rates and its application in high-velocity penetration

引用

Journal of Materials Science & Technology 2023年第1期132卷 144-153页

作者： weiqi Tang Kun Zhang Tianyu Chen Qiu Wang bingchen wei Key Laboratory of Microgravity(National Microgravity Laboratory) Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

Energetic structural materials(ESMs)integrated a high energy density and rapid energy release with the ability to serve as structural materials.Here,a novel triple-phase TiZrHfTa_(0.7)W_(0.3)high-entropy alloy(HEA)was fabricated and investigated as a potential ESM.A hierarchical microstructure was obtained with a main metastable body-centered-cubic(BCC)matrix with distributed Ta-W-rich BCC precipitates of various sizes and interwoven hexagonal close-packed(HCP)lamellar nano-plates.The compressive me-chanical properties were tested across a range of strain rates and demonstrated a brittle-to-ductile tran-sition as the strain rate increased while maintaining a high ultimate strength of approximately 2.5 GPa.This was due to the phase transformation from metastable matrix BCC to HCP structures.In addition,during the dynamic deformation,metal combustion originating from the failure surface was observed.Furthermore,the composition of the fragments was studied,and the results indicated that the addition of tungsten promoted combustion.Finally,the potential application of this HEA was evaluated by high-velocity penetration tests,and the results were compared to other typical structural materials for pene-trators and bullets.A comparison was conducted by assessing the geometries of the penetration channel employing two dimensionless parameters normalized by the projectile size,representing longitudinal and lateral damage,respectively.The normalized depth of the TiZrHfTa_(0.7)W_(0.3)HEA projectile was comparable to those of the other investigated materials,but the normalized diameter was the largest,showing an excellent ability to deliver lateral damage.

关键词： Energetic structural materials High-entropy alloys Phase transformation Ballistic tests

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Preparation of Cu-based Bulk Metallic Glass Matrix Composites

引用

Journal of Materials Science & Technology 2006年第1期22卷 73-77页

作者： Yufeng SUN Yuren WANG bingchen wei weihuo LI Research Center for Materials Department of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450002 China National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

在 situ 包含的金属性的玻璃(BMG ) 矩阵 composites 形成了的 Cu_(47 )Ti_(34 )Zr_(11 ) Ni_8 体积 TiC 粒子和 delta-TiCu 树突阶段被铜开发模子演员组。composites 的热稳定性和微观结构被调查。房间温度耐压试验表明合成样品展出更... 详细信息

在 situ 包含的金属性的玻璃(BMG ) 矩阵 composites 形成了的 Cu_(47 )Ti_(34 )Zr_(11 ) Ni_8 体积 TiC 粒子和 delta-TiCu 树突阶段被铜开发模子演员组。composites 的热稳定性和微观结构被调查。房间温度耐压试验表明合成样品展出更高的破裂力量和 0.2 percent-0.5 百分比的不同塑料紧张，把 Ti_(34 ) 与 correspondingCu_(47 ) 的作比较 Zr_(11 ) Ni_8 整体的 BMG。

关键词：金属玻璃剪切带机械性能铜基复合物

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Phase transition and heterogeneous strengthening mechanism in CoCrFeNiMn high-entropy alloy fabricated by laser-engineered net shaping via annealing at intermediate-temperature

引用

Journal of Materials Science & Technology 2021年第33期92卷 129-137页

作者： Yunjian Bai Heng Jiang Kuo Yan Maohui Li Yanpeng wei Kun Zhang bingchen wei Key Laboratory of Microgravity(National Microgravity Laboratory) Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100190China Institute of Quartermaster Engineering&Technology Academy of System EngineeringAcademy of Military SciencesBeijing 100049China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100049China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100010China

High-entropy alloys(HEAs)have attracted tremendous attention owing to their controllable mechanical properties,whereas additive manufacturing(AM)is an efficient and flexible processing route for novel materials design.However,a profound appraisal of the fundamental material physics behind the strengthening of AM-printed HEAs upon low/intermediate-temperature annealing is essential.In this work,Co CrFe Ni Mn HEAs have been prepared using laser-engineered net shaping(LENS)and subsequently annealed at different temperatures.The Co Cr Fe Ni Mn HEA annealed at intermediate-temperature(873 K)exhibits a strong strain hardening capability,resulting in ultimate strength of 725 MPa and plasticity of 22%.A ternary heterogeneous strengthening mechanism is proposed to explain this phenomenon,in which equiaxed grains,columnar grains,andσprecipitates play different roles during tensile deformation.The resultant excellent strength and ductility can be ascribed to the heterostructure-induced mismatch.The equiaxed grains provide adequate grain boundaries(GBs),which induce dislocation plugging-up and entanglement;the columnar grains induce the onset and arrest of the dislocations for plastic deformation;and theσprecipitates hinder the movement of slip dislocations.The results provide new insights into overcoming the strength-ductility trade-off of LENS-printed HEAs with complex geometries.

关键词： High-entropy alloys Phase transition Heterogeneous strengthening Intermediate-temperature

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An Online Website Fingerprinting Defense Based on the Non-Targeted Adversarial Patch

引用

Tsinghua Science and Technology 2023年第6期28卷 1148-1159页

作者： Xiaodan Gu bingchen Song wei Lan Ming Yang School of Computer Science and Engineering Southeast UniversityNanjing 211189China

Website Fingerprinting(WF)attacks can extract side channel information from encrypted traffic to form a fingerprint that identifies the victim’s destination website,even if traffic is sophisticatedly anonymized by Tor.Many offline defenses have been proposed and claimed to have achieved good effectiveness.However,such work is more of a theoretical optimization study than a technology that can be applied to real-time traffic in the practical scenario.Because defenders generate optimized defense schemes only if the complete traffic traces are obtained.The practicality and effectiveness are doubtful.In this paper,we provide an in-depth analysis of the difficulties faced in porting existing offline defenses to the online scenarios.And then the online WF defense based on the non-targeted adversarial patch is proposed.To reduce the overhead,we use the Gradient-weighted Class Activation Mapping(Grad-CAM)algorithm to identify critical segments that have high contribution to the classification.In addition,we optimize the adversarial patch generation process by splitting patches and limiting the values,so that the pre-trained patches can be injected and discarded in real-time traffic.Extensive experiments are carried out to evaluate the effectiveness of our defense.When bandwidth overhead is set to 20%,the accuracies of the two state-of-the-art attacks,DF and Var-CNN,drop to 10.83%and 15.49%,respectively.Furthermore,we implement the real-time patch traffic injection based on WFPadTools framework in the online scenario,and achieve a defense accuracy of 95.50%with 12.57%time overhead.

关键词： website fingerprinting online defense adversarial patch traffic analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A SAR imaging method based on generalized minimax-concave penalty

引用

Science China(Information Sciences) 2019年第2期62卷 233-239页

作者： Zhonghao wei bingchen ZHANG Yirong WU University of Chinese Academy of Sciences Key Laboratory of Technology in Geospatial Information Processing and Application Systems Institute of Electronics Chinese Academy of Sciences Institute of Electronics Chinese Academy of Sciences

Dear editor,Sparse signal processing offers a framework for synthetic aperture radar （SAR） imaging [1, 2]. As an efficient tool in sparse signal processing, L1minimization is often used in the reconstruction of SAR images. When implemented in SAR imaging [3–5], L;minimization offers significant improvement in the properties by suppressing the sidelobes and clutter. However, L;minimization is known to be a biased estimator. The L;minimization based algorithms such as the iterative

关键词： SAR A SAR imaging method based on generalized minimax-concave penalty

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Deformation behavior of Fe-based bulk metallic glass during nanoindentation

引用

Science China(Physics,Mechanics & Astronomy) 2008年第4期51卷 365-371页

作者： LI Lei LIU Yuan ZHANG TaiHua GU JianSheng wei bingchen National Microgravity Laboratory Institute of MechanicsChinese Academy of SciencesBeijing 100080China State Key Laboratory of Nonlinear Mechanics(LNM) Institute of MechanicsChinese Academy of Sci-encesBeijing 100080China

Fe-based bulk metallic glasses (BMGs) normally exhibit super high strength but significant brittleness at ambient temperature. Therefore,it is difficult to investigate the plastic deformation behavior and mechanism in these alloys through conven-tional tensile and compressive tests due to lack of distinct macroscopic plastic strain. In this work,the deformation behavior of Fe52Cr15Mo9Er3C15B6 BMG was in-vestigated through instrumented nanoindentation and uniaxial compressive tests. The results show that serrated flow,the typical plastic deformation feature of BMGs,could not be found in as-cast and partially crystallized samples during nanoinden-tation. In addition,the deformation behavior and mechanical properties of the alloy are insensitive to the applied loading rate. The mechanism for the appearance of the peculiar deformation behavior in the Fe-based BMG is discussed in terms of the temporal and spatial characteristics of shear banding during nanoindentation.

关键词： bulk metallic glass nanoindentation serrated flow shear band

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microstructure and mechanical properties of a novel Zr-based bulk metallic glass composite

引用

Chinese Science Bulletin 2005年第24期50卷 2804-2808页

作者： SUN Yufeng WANG Yuren GUO Jian wei bingchen LI weihuo National Microgravity Lab Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Research Central for Materials Department of Materials Science and Engineering Zhengzhou University Zhengzhou 450002 China Department of Materials and Chemical Engineering Zhongyuan In- stitute of Technology Zhengzhou 450002 China

Zr48.5Cu46.5Al5 bulk metallic glass (BMG) com- posites with diameters of 3 and 4 mm were prepared through suction casting in an arc melting furnace by modulating the alloy composition around the monothetic BMG composition of the high glass forming ability. Microstructural charac- terization reveals that the composites contain micron-sized CuZr phase with martensite structure, as well as nano-sized Zr2Cu crystalline particles and Cu10Zr7 plate-like phase em- bedded in an amorphous matrix. Room temperature com- pression tests showed that the composites exhibited signifi- cant strain hardening and obvious plastic strain of 7.7% for 3 mm and 6.4% for 4 mm diameter samples, respectively.

关键词：金属玻璃剪切带塑性变形微观结构力学性质

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Domain structure of hard magnetic NdAlFeCo bulk metallic glass

引用

Chinese Science Bulletin 2001年第19期46卷 1595-1598页

作者： wei bingchen WANG weihua PAN Mingxiang HAN Baoshan ZHANG Zhenrong HU Wenrui National Microgravity Laboratory Institute of MechanicsBeijing 100080China Institute of Physics and Center for Condensed Matter Physics Chinese Academy of SciencesBeijing 100080China State Key Laboratory of Magnetism Institute of Physics and Center for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080China

Magnetic domain structure of hard magnetic Nd60Al10Fe20Co10 bulk metallic glass (BMG) has been studied by using magnetic force microscopy. In the magnetic force images it is shown that the exchange interaction type magnetic domains with a period of about 360 nm do exist in the BMG, which is believed to be associated with the appearance of hard-magnetic properties in this system. As the scale of the magnetic domain is much larger than the size of the short-range ordered atomic clusters existing in the BMG, it is believed that the large areas of magnetic contrast are actually a collection of a group of clusters aligned in parallel by strong exchange coupling interaction. After fully crystallization, the BMG exhibits paramagnetism. No obvious magnetic contrast is observed in the magnetic force images of fully crystallized samples, except for a small quantity of ferromagnetic crystalline phase with low coercivity and an average size of 900 nm.

关键词： metallic glass hard magnetism magnetic force microscopy exchange coupling interaction.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Deformation behavior during nanoindentation in Ce-based bulk metallic glasses

引用

Chinese Science Bulletin 2006年第13期51卷 1639-1643页

作者： ZHANG Lingchen XING Dongmei ZHANG Taihua wei bingchen LI weihuo WANG Yuren National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China College of Physics and Electronic Information Science Tianjin Norreal University Tianjin 300072 China

The deformation behavior and the ef- fect of the loading rate on the plastic deformation in Ce-based bulk metallic glasses (BMGs) were inves- tigated through nanoindentation tests. The results showed that the loading rate dependence of plastic deformation during nanoindentation measurements in the Ce-based BMGs is quite unique in contrast to that of other BMG alloys. The load-displacement (P-h) curves of Ce60Al15Cu10Ni15 BMG exhibit a homoge- neous plastic deformation at low loading rates, and a prominent serrated flow at high strain rates, whereas, the P-h curves of Ce65Al10Cu10Ni10Nb5 exhibit ho- mogenous plastic deformation at all studied loading rates. The room temperature creep behavior could clearly be observed in these two alloys. The mecha- nism of the unique plastic deformation feature in the Ce-based BMGs was studied.

关键词：大块金属玻璃纳米凹痕锯齿流蠕变

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

气相爆轰驱动二级轻气炮内弹道数值模拟

引用

力学学报 2022年第3期54卷 810-821页

作者：尚甲豪邢好运汪球李进平赵伟魏炳忱中国科学院力学研究所高温气体动力学国家重点实验室北京100190 中国科学院大学工程科学学院北京100049 中国科学院力学研究所国家微重力实验室北京100190

二级轻气炮是超高速弹丸驱动技术中使用最广泛的技术之一,它在超高速气动物理现象及材料高速碰撞下力学性能的实验研究和验证方面起着不可或缺的作用.中国科学院力学研究所基于爆轰驱动方法研制了一座大型二级轻气炮,可弥补高压气体驱... 详细信息

二级轻气炮是超高速弹丸驱动技术中使用最广泛的技术之一,它在超高速气动物理现象及材料高速碰撞下力学性能的实验研究和验证方面起着不可或缺的作用.中国科学院力学研究所基于爆轰驱动方法研制了一座大型二级轻气炮,可弥补高压气体驱动能力有限和火药使用受限的不足.本文基于经过实验验证的准一维数值模拟方法,详细研究了该设备的内弹道动力学参数及发射性能,并探讨了不同发射方法及装填参数对设备性能的影响规律和机理.研究结果表明,氢氧爆轰驱动相比于高压气体驱动具有明显优势;不同爆轰驱动方式对弹丸发射性能影响较小,但其影响到整个设备的强度设计;对装填运行参数的研究表明增大爆轰段充气压力可以有效加强轻气炮发射性能,而活塞质量变化对发射速度的影响较为复杂,轻气炮实际运行中受设备设计指标及模型材料性能的限制,优化过程中需要同时调整3种参数以达到轻气炮最佳性能.

关键词：爆轰驱动轻气炮数值模拟发射性能内弹道

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：